Core support for a centrifugal casting mould for casting pipes having a socket, and mould provided with said support



CORE SUPPORT FOR A CENTRIE'UGAL CASTING MOULD FOR CASTING PIPES HAVING ASOCKET, AND

MOULD PROVIDED WITH SAID SUPPORT Filed July 18, 1966 2 Sheets-Sheet lNov. 26, 1968 P. E. LORANG 3,412,785

Fig.2

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P/ena dav d LaRANfi Nov. 26, 1968 P. E LORANG 3,412,785

CORE SUPPORT FOR A CENTRIFUGAL CASTING MOULD FOR CASTING PIPES HAVING ASOCKET, AND

MOULD PROVIDED WITH SAID SUPPORT Filed July 18, 1966 2 Sheets-Sheet 2Fig.3

T 'l I iz v //VV-N 7'8 R Pierre. Edouard LORANG- United States Patent M9 Claims. (a. 164-292) The present invention relates to centrifugalcasting moulds for casting pipes having a socket and in particular butnot exclusively to moulds for casting cast iron pipes.

It is known that moulds of this type comprise a core which imparts theinternal shape of the socket. This core is supported by a device (yoke)comprising centering means for centering it in the mould and lockingmeans for maintaining it firmly in position in the course of thehigh-speed rotation of the mould and resisting the centrifugal pressureof the liquid iron.

As the core is of sand and is used for only one casting operation, notonly must its support be withdrawable as is known by pivoting or tiltingso as to permit the extraction of the cast pipes and the replacement ofthe destroyed core by a fresh core, but the support must be so designedas to permit rapidly positioning and perfectly centering each new core.

Core-locking devices are known which comprise lugs which projectradially relative to the bearing face at the end of the mould so as toretain the core by the abutment of its end face against said lugs. Thelatter can project internally under the action of springs or of thecentrifugal force when the mould rotates. They are mounted in suchmanner that they are exposed to projections of liquid iron which occurwhen the latter sometimes is in excess in the pipe socket zone.Consequently, it is sometimes necessary to remove the pieces of excessiron which may block the locking device and this is a loss of time andslows down production. Further, the lug-type locking devices areconnected to the mould. This arrangement does not lend itself well to amechanical feeding of the cores.

The object of the invention is to provide for a centrifugal castingmould for casting pipes having a socket, a socket core support whichensures in a simple and effective manner the locking of said cores andis unexposed to the projections of iron and adaptable to a mechanicalfeeding of the cores.

According to the invention, the core support or yoke, mounted at the endof a swingable handling arm, for a centrifugal casting mould comprisesin combination a cup for supporting and centering the core and extendedby an outwardly divergent deflecting cone; a locking ring inserted withclearance in the cup coaxially of the latter; compressed air blowingmeans for blowing air between the locking ring and the end face of therecess for the ring in the cup, a handling stirrup mounted at its endson the locking ring to be pivotable about an axis intersecting the axisof rotation of the mould, and a handling arm on the end of which thestirrup is mounted to be slightly pivotable about an axis perpendicularto the pivot axis of the stirrup on the locking ring.

Another object of the invention is to provide a centrifugal castingmould for casting pipes having a socket, said mould including a coresupport of the above-described type.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawings.

In the drawings:

Patented Nov. 26, 1968 FIG. 1 is a diagrammatic view, partly in section,of a mould according to the invention;

FIG. 2 is a partial end view taken along line 2--2 of FIG. 1, and

FIG. 3 is a detailed sectional view, on an enlarged scale, of the coresupport according to the invention.

In the embodiment shown in FIGS. 1 and 2, the invention is shown to beapplied to a rotary mould M having a roughly honizontal axis X-X andintended for centrifugally casting a pipe T having a socket and composedfor example of cast iron. This mould comprises two rolling rings 1 whichcooperate with two pairs of support rollers 2 mounted between bearings3. A motor 4 rotates the rollers 2 of one of said pairs of rollers. Theassembly is mounted on a centrifugal casting machine which isrepresented diagrammatically by its casing C.

The mould M comprises at the end thereof adjacent the socket of the pipeT to be obtained (FIGS. 1 and 3), a divergent cavity 5 in the form of atulip or bell which is enlarged at the entrance thereof in the form oftwo successive cylindrical recesses, namely recess or housing 6 for acore N which imparts the inner shape to the socket, and recess orhousing 7 which is of greater diameter for supporting said core. Thedivergent cavity 5 is separated from the core recess 6 by a transverseface 8. The recess 7 is connected to the exterior by a divergent conicalentrance portion 9 or countersinking.

The core N is for example of sand. It comprises near its end a flange 10which acts as a print for the end face of the pipe and bears on thetransverse face 8 located between the bell 5 and recess 6. The core isextended beyond the flange 10 by a cylindrical male support or bearingface 11.

The core or yoke support S according to the invention comprises threeparts:

A rotary core support and centering cup.

A rotary cone for protecting against projection of iron, or deflectingcone.

A locking ring which is prevented from rotating and mounted on ahandling stirrup carried by a swingable arm for placing in position orwithdrawing the core support S.

This support S of the core N therefore comprises a cup 12 having theshape of a circular plate and an axis XX and a diameter slightly lessthan that of the recess 7. This cup has an axial bore or aperture 13whose diameter corresponds to that of the diameter of the bearing face11 for the core N. This bore 13 thus constitutes a centering supportface for this core. The cup 12 comprises on one side an annular planeface 14 for urging the flange 10 of the core against the transverse face8 of the mould. The face 14 corresponds to the face 8 of the mould andis inwardly defined by an inner recess 15.

The cup 12 is extended beyond the support face 13 by an outwardlydivergent deflecting cone 16 which has an axis XX and is adapted toprotect the locking means of the support S from projections or splashesof iron.

The cup 12 is provided with an annular recess or housing 17 having anaxis XX on the side of the cup opposed to the face 14, that is, adjacentthe deflecting cone 16. A locking ring 18 is inserted with clearance inthe recess 17.

The locking ring 18 is provided with an annular groove 19 on itsperiphery in which groove is engaged the teat of at least one clampingscrew 20 which is radially screwed into the wall of the cup 12 so as tointerconnect the cup 12 and the locking ring 18 axially but not asconcerns rotation, the end teat of each screw 20 extending into theinterior of the annular recess 17. The groove 19 has a width exceedingthe diameter of the teat or teatsso that there is a certain amount ofaxial play between the cup 12 and the locking ring 18.

This locking ring 18 is provided internally with an annular cavity 21having an axis X-X. Communicating with this cavity 21 is the aperture ofa connection element 22 located at the end of a flexible conduit 23supplying compressed air. On its opposite face adjacent the end face ofthe recess 17, the ring 18 is provided with a number of blowing orifices24 which are disposed on a circle and communicate with the cavity 21.

Preferably, a friction ring 25, having roughly the same diameter as thelocking ring, is interposed between the latter and the recess 17 in thecup 12. This ring 25 can be of plastics material, such as red fibre,Teflon or of antifriction metallic material such as bronze orlead-antimoine alloys or of a combination of plastics materials andmetallic materials.

As mentioned hereinbefore, the core support or yoke S is carried by ahandling device. This will now be described with reference to FIGS. 1and 2.

The locking ring 18 comprises a pair of ears 26 which are diametricallyopposed. Mounted on these ears to pivot about a diametrical axis YY arethe ends of a handling stirrup E. The stirrup E is itself pivotablethrough a few degrees at 27 on the end of a swingable handling arm B.The pivotal connection 27 of the stirrup E to the arm B has an axis ZZwhich is perpendicular to the pivot axis of the stirrup E on the ears26. The pivotal connection 27 is retained axially by a locking device ofknown type, for example pins 28 which engage with a slight clearance inapertures 29 formed in the pivot 27.

The pivotal connections of the stirrup E to the cars 26 of the ring 18and to the pivot 27 of the arm B advantageously constitute in accordancewith the invention a floating mounting of the support assembly S.

The swingable arm B is carried by a shaft D having an axis parallel tothe axis X-X mounted outside the machine so as to be rotatable through afraction of a revolution and movable axially in the known manner. Forthis purpose, it is mounted in the known manner in the extension of thepiston rod of a jack V to which it is connected as concerns axialmovement by a coupling A which allows it to rotate. The shaft D isdriven in rotation a fraction of a revolution in the known manner forexample by a transverse jack W which actuates a lever 30 connected to asleeve 31 slidably keyed to the shaft D. The jacks V and W are fixed tothe outside of the centrifugating machine.

This machine permits the introduction and withdrawal of the core N fromthe mould M and the swinging of the support S outside the axis of themould (position of the arm B shown in dot-dash line in FIG. 2) so thatthe mould pipe T can then be withdrawn and the mould can receive a newcore N.

This machine operates in the following manner:

When the mould has stopped rotating, the support S is withdrawn from themould by the action of the jack V and swung through a fraction of arevolution by the action of the jack W so that a core N can be placed inposition. This core is therefore introduced in the centering support orhearing face 13 of the support S until its flange is applied against theface 14 of the cup 12. Thereafter, the jacks W and V are actuated insuccession so as to return the support S to the position in which it iscoincident with the axis XX of the mould and insert the core N in themould.

Owing to the floating mounting on the handling arm B (axial clearancebetween the clamping screws and the groove 19), the pivotal mounting ofthe stirrup E on the ears 26 of the ring 18 and the pivot 27, thesupport S is freely centered by its cup 12 in its housing or recess 7 inthe mould. The support S tends to apply the flange 10 of the coreagainst the transverse face 8 at the inner end of the recess 6. The coreis held perfectly flat against the face 8 of the mould in the mannerdescribed hereinafter.

With the mould M still stationary, air is supplied at a pressure of atleast 1 bar to the flexible conduit 23. This air is blown through theapertures 24 over the annular contact face between the friction ring 25and the locking ring 18. A film or layer of compressed air is thuscreated between the two rings.

The friction ring 25 is thus thrust away from the locking ring 18 andflat against the inner end of the annular recess 17 in the cup 12.Consequently, the axial locking thrust of the ring 18, which isprevented from rotating, on the rotary cup 12 is exerted through thefriction ring 25. In this way a perfect abutment of the core N againstthe face 8 of the mould is achieved. When the mould M is driven inrotation, the core N (which is urged against the mould) and its supportS (cup 12 and deflecting cone 16) are driven in rotation at the samespeed as the mould. The friction ring 25 also has a tendency to rotateowing to the fact that it is in contact with the inner end face of theannular recess 17 of the cup 12. On the other hand, owing to thecompressed air between the locking ring 18 and friction ring 25 thislocking ring is perfectly independent of the movement of rotation. Thefilm of compressed air therefore permits a non-rotary member (ring 18)to exert a thrust on a rotary member (cup 12).

During the casting, when the molten iron reaches the socket region ofthe mould, it fills the space between the core N and the mould M.

If iron in excess is thrown out of the mould, the deflecting cone 16prevents the centrifugal projections or splashes from reaching thelocking ring 18. Thus, the support S is perfectly protected as concernsits locking means by the deflecting cone 16.

It will be observed moreover that owing to the cylindri cal corecentering and support face 11, the face 13 of the cup 12 is protectedfrom possible contact with the liquid iron and this avoids an excessiveheating of the cup. Further, the escape of compressed air from the filmof air along the walls of the annular recess 17 in the cup 12 helps tocool continuously the latter whose temperature during casting remainsmoderate.

Owing to the annular clearance between the ring 18 and the recess 17 andthe floating mounting of the support S on the handling arm B by means ofscrews 20 engaged with clearance in the groove 19 of the cup, thepivotal connections of the cars 26 of the ring 18 and pivot 27 of thestirrup E, the cup 12 is constantly thrust flat against the core N, evenif the mould M should rotate in a noncircular manner, that is,oscillates about its axis X-X.

Further, owing to the groove 19 in the cup 12 and the retaining screws20 engaged with clearance in said groove, the cup 12 remains connectedto the locking ring 18 when the arm B is shifted axially and swunground.

At the end of the casting operation the support S for the core iswithdrawn and the arm B swung laterally so as to permit the withdrawalof the pipe T and the placing in position of a new core N on the cup 12.

Although a specific embodiment of the invention has been described, manymodifications and changes may be made therein without departing from thescope of the invention as defined in the appended claims.

Thus, although the invention has been more particularly described inrelation to the moulding of cast iron pipes, it is also applicable tothe moulding of pipes having a socket and composed of plastics material,such as a thermosetting resin, or of a material having a cement base(concerte, asbestos-cement).

In this case the socket core can be of plastics, elastic or metallicmaterial.

Further, instead of being in one piece with the cup 12, the deflectingcone 16 can be detachably secured to the latter.

Having now described my invention what I claim as new and desire tosecure by Letters Patent is:

1. A core support for a centrifugal casting mould for casting a pipehaving a socket, said support comprising in combination: a cup forsupporting and centering the core and having an annular recess andextended by an outwardly divergent deflecting cone; a locking ringinserted with clearance in the recess in the cup coaxially of thelatter; compressed air blowing means for blowing air between the lockingring and the inner end face of the recess in the cup, a handling stirnupmounted at its ends on the locking ring to be pivotable about an axisintersecting the axis of rotation of the mould, and a handling arm onthe end of which the stirrup is mounted to be slightly pivotable aboutan axis perpendicular to the pivot axis of the stirrup on the lockingring.

2. A core support as claimed in claim 1, wherein the core comprises amale cylindrical support face and the cup comprises a correspondingfemale cylindrical support face in which said male support face isinserted and centered.

3. A core support as claimed in claim 1, wherein the cup comprises aplane transverse face which adjoins a flange of the core, said flangebeing applied against a transverse plane face on the mould by the axialthrust exerted by said plane transverse face of the cup.

4. A core support as claimed in claim 3, wherein the cup comprises, onthe side thereof opposed to the face adjoining the flange of the core,an annular recess in which the locking ring is inserted with clearance.

5. A core support as claimed in claim 3, wherein blowing aperturesextend through the locking ring and communicate with the face of thering adjacent the inner end face of the recess of the cup in which thering is inserted.

6. A core support as claimed in claim 1, wherein the locking ring isprovided with a pair of diametrally opposed ears which are connected tothe stirrup for pivotal movement about a diametral axis, the pivotalaxis of the stirrup on the end of the swingable arm being perpendicularto said diametral axis.

7. A core support as claimed in claim 1, wherein the locking ring isprovided with an annular groove and a screw having a retaining teat,said screw threadedly extending through the Wall of the cup surroundingsaid recess and projecting inwardly of the annular recess of the ring soas to engage with clearance said groove and thus axially interconnectsaid cup and said ring with play.

8. A core support as claimed in claim 1, wherein a riction ring isinterposed between the locking ring and the cup at the inner end of theannular recess in the cup for the locking ring.

9. A mould and core for centrifugal casting combined with a core supportcomprising in combination: a cup for supporting and centering the coreand having an annular recess and extended by an outwardly divergentdeflected cone; locking ring inserted with clearance in the recess inthe cup coaxially of the latter; compressed air blowing means forblowing air between the locking ring and the inner end face of therecess in the cup, a handling stirrup mounted at its end on the lockingring to be pivotable about an axis intersecting the axis of rotation ofthe mould, and a handling arm on the end of which the stirrup is mountedto be slightly pivotable about an axis perpendicular to the pivot axisof the stirrup on the locking ring.

References Cited UNITED STATES PATENTS 2,267,815 12/1941 Bush. 2,517,3178/1950 Janco 164292 3,040,395 6/1962 Warkoczewski 164-302 X 3,074,1301/1963 Wittmoser et al. 164-302 X 3,168,765 2/1965 Bernhardt 164-302 I.SPENCER OVERHOLSER, Primary Examiner.

EUGENE MAR, Assistant Examiner.

1. A CORE SUPPORT FOR A CENTRIFUGAL CASTING MOULD FOR CASTING A PIPEHAVING A SOCKET, SAID SUPPORT COMPRISING IN COMBINATION: A CUP FORSUPPORTING AND CENTERING THE CORE AND HAVING AN ANNULAR RECESS ANDEXTENDED BY AN OUTWARDLY DIVERGENT DEFLECTING CONE; A LOCKING RINGINSERTED WITH CLEARANCE IN THE RECESS IN THE CUP COAXIALLY OF THELATTER; COMPRESSED AIR BLOWING MEANS FOR BLOWING AIR BETWEEN THE LOCKINGRING AND THE INNER END FACE OF THE RECESS IN THE CUP, A HANDLING STIRRUPMOUNTED AT ITS ENDS ON THE LOCKING RING TO BE PIVOTABLE ABOUT AN AXISINTERSECTING THE AXIS OF ROTATION OF THE MOULD, AND A HANDLING ARM ONTHE END OF WHICH THE STIRRUP IS MOUNTED TO BE SLIGHTLY PIVOTABLE ABOUTAN AXIS PERPENDICULAR TO THE PIVOT AXIS OF THE STIRRUP ON THE LOCKINGRING.